In the past, we have substantially increased the resolution and sensitivity of the technique by introducing diffusional deconvolution to the calculation of sedimentation coefficient distributions. This has become the new state-of-the-art of sedimentation velocity analytical ultracentrifugation and is widely applied by research laboratories in this field. Further building on this, we have developed a method to combine the Edelstein-Schachmann density contrast technique with sedimentation coefficient distributions. This will be helpful to determine with greater precision the partial-specific volume of particles, such as proteins, liposomes, and nucleic acids. In initial tests of this approach with various particles, we have confirmed its feasibility. We have continued to explore in theory and experiment the influence of binding kinetics on the sedimentation profile of interacting systems, and we have continued our effort of modeling the dynamics of fibrillar assembly and the sedimentation properties of dynamic fibrillar systems. On the theoretical side, we have further extended the effective particle model to approximate the diffusional spread of a reaction boundary. Finally, we have begun to confirm experimentally some of the predictions of the effective particle model, and exploit the predictions of new profitable experimental configurations. The effective particle model was also utilized to build a tool for researchers to better plan sedimentation velocity experiments of interacting systems. Further, we have created a visual protocol for colleagues to accomplish ultracentrifugal cell assembly. Also, we have analyzed different mathematical approaches to account for radial-dependent signal offsets in ultracentrifugal data sets.